I remember learning that there is a mitzvah to give testimony if you know of something which it requires. My question is if you know about yourself, with certainty, that you are pasul l'eidus in general, for whatever the reason, but the court does not know that you are pasul l'eidus, do you still have a mitzvah to go give testimony?

If the answer is dependent on the pesul please indicate what the difference would be and why.

You should probably ask if you are allowed to give testimony if you are an invalid witness. Also, are you talking about a biblical p'sul or a rabbinic p'sul? (Also, if you think this might be a practical question, CYLOR regarding whether you are actually pasul l'eidus).
– FredDec 29 '14 at 1:18

3

This is an excellent question, though I'm not sure if the OP realizes why: if a person knows about himself to be be disqualified because of his legal violations, then the court wouldn't believe him, and can therefore (seemingly) force him to testify... Even though he thinks that it's prohibited for himself to testify!
– הנער הזהDec 29 '14 at 2:59

If that's your question I'd suggest you clarify (and if so there's a very big difference between a pesul rishus, a disqualification based on wickedness, and a pesul gavra, a personal disqualification, such as saying that you were a child at the time of the event)
– הנער הזהDec 29 '14 at 17:42

@Matt look in the pischei tshuva in the answer. He brings from r' Yonason Eibshitz the point that a person can't invalidate himself. He doesn't focus on the belief of his words in Beis Din, it seems fundamental that he cannot make himself passul from aveira, even as far as he himself is concerned! (It's really good tshuva drashah material:)
– user6591Dec 30 '14 at 1:21

1 Answer
1

It seems from Shulchan Aruch, Choshen Mishpat 34 that the prohibition against testifying in a situation of being ineligible to do so, at least in a case where the disqualifier is because the witness is a "rasha," is incumbent on the witness himself. The case there is where a kosher witness knows that his fellow witness is ineligible to testify, but is actually going to say the truth and through the two of them justice would be carried out. This is not allowed. A kal vichomer (a fortiori argument) would apply when he knows he himself is disqualified.

This proof is actually quoted in the Pischei Tshuva there, #1 in the name of Chavos Yair. But see there as he brings other opinions discussing different rulings depending on what the disqualifier is.